Society and the Environment: Ocean Currents

A shipment of rubber ducks lost at sea helped scientists study ocean current movements.

Ocean currents are important in transporting heat, water, nutrients, pollutants, and organisms around the world. Even though they are important, ocean currents have been hard to study. Scientists used to drop labeled bottles in the oceans in different places and then recorded where they were picked up. Now, oceanographers attach transmitters to drifters. These transmitters send their position to satellites overhead, providing scientists with information that is helpful in a variety of ways, from protecting endangered species to making important decisions with far-reaching effects.

Watch Out For Debris!
The Hawaiian monk seal is one of the most endangered marine mammals in the world, with a population around 1,200 individuals. Monk seals live in the remote Northwest Hawaiian Islands (NWHI), hundreds of kilometers from the nearest human populations. Unfortunately, many seals have still been killed when they were entangled in discarded fishing gear that was dumped into the ocean hundreds or thousands of kilometers away. This is because the currents of the Pacific Ocean carry the debris to the areas where the seals feed, rest, and have their pups. Since 1996, around 500 metric tons of debris have been removed from the beaches of the NWHI! This has helped keep monk seals safer, but the currents keep bringing more debris to Hawaii, so these efforts must continue.

Oil Drilling
In order to meet the energy demands of the world, it is necessary to drill oil wells in deep ocean waters. During the summer of 2010, the Deepwater Horizon oil platform exploded and sank, releasing about five million barrels of oil into the Gulf of Mexico. Understanding currents was critical to responding appropriately to the spill. The Loop Current could have taken oil from off of Louisiana to the Florida Keys and even up the East Coast of the U.S. Luckily, the loop current did not form in a way to take oil south. Instead, the oil stayed relatively close to the spill. In fact, the currents kept the oil in a place where bacteria could help to break it down, possibly reducing the impact of the spill.

Toys Ahoy!!
Despite more advanced methods, data that help us understand ocean currents sometimes comes from the most unusual sources! In 1992, a container ship traveling northwest of Hawaii ran into a storm. One of the containers that washed overboard held 29,000 plastic toys. Over the next few years, the toys began washing up along the Alaskan coast from Sitka to the Bering Sea. Comparing data from the toys with other data, the researchers concluded that, although the current across the northeast Pacific Ocean changes little from year to year, in 1990 and 1992 the current was unusually far north.